dbcve.org
Iphone OsOperating system · Apple

CVE-2011-0159

MEDIUM · 5.0 CVSS v2.0 Published 2011-03-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The Safari Settings feature in Safari in Apple iOS 4.x before 4.3 does not properly implement the clearing of cookies during execution of the Safari application, which might make it easier for remote web servers to track users by setting a cookie.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Safari Settings feature in Safari on iOS 4.x before 4.3 fails to properly clear cookies when users attempt to do so through the Settings interface. This implementation flaw allows cookies to persist even after users request their deletion, enabling remote web servers to continue tracking users via cookies.

MitigationUpdate iOS to version 4.3 or later, which contains the patch for this Safari cookie-clearing vulnerability. For legacy systems that cannot be updated, users should be aware that manual cookie clearing through Safari Settings may not be fully effective.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Iphone OsOperating system
Affected:= 4.0= 4.1= 4.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None

AV:N/AC:L/Au:N/C:P/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check iOS version on the device
    Navigate to Settings > General > About > Version on the iOS device
    Affected if The displayed version reads 4.0, 4.1, or 4.2 exactly
  2. Confirm Safari is used for web browsing
    Verify that Safari is the default browser and has been used to visit websites that set cookies
    Affected if Safari has been used to browse the web and cookies exist in Safari's storage
  3. Attempt cookie clearing via Settings
    Go to Settings > Safari > Clear Cookies and Data, then check if cookies persist by visiting a site that sets a test cookie
    Affected if Cookies remain after attempting to clear them through the Safari Settings interface

The device is affected if it runs iOS 4.0, 4.1, or 4.2 and cookies persist after using the Clear Cookies and Data option in Safari Settings.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update iOS to version 4.3 or later, which contains the patch for this Safari cookie-clearing vulnerability. For legacy systems that cannot be updated, users should be aware that manual cookie clearing through Safari Settings may not be fully effective.

Fix this in Iphone Os Scoped from the published advisory
  • Consultation1.0 h
  • Review / QA1.0 h
2.0 hours of engineering $750
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2011-0159 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2011-0159 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data